The use of ambulatory, mechanically driven infusion devices or pumps have gain wide acceptance due to its ease of use, safe and effective means of drug delivery in both hospital and non-hospital based settings. The salient benefits are derived from the absence of programming or infusion settings, unlike electronic pumps which can lead to serious adverse events arising from human errors.
The general principle of such mechanical pumps is based on a force or pressure action on a body of fluid within an enclosed container or receptacle such that the fluid is pushed out through a flow restrictor connected to the container. For any given pressure acting on the fluid, the flow rate achieved is determined by the internal diameter of the lumen of the restrictor based on Bernoulli's and/or Hagen principle.
Albeit the safety element imbued in mechanical pumps, there are limitations that relates to flow accuracy and costs, particularly when the pump is intended for single use only. The flow rate accuracy which is typically designed to meet prevalent international standards of +/−15% limits the device to its use with only drugs that allow greater tolerant ranges. There are also other issues pertaining to storage and operational use, for example if the device is constructed with elastomeric membranes as reservoir, the pressure generated would be affected by the time duration and conditions of storage.